The popular college on Crown Road has completed its interviews this week and confirmed its course offerings for next term, which reveal the student roll will have grown from 403 in 2011 to an expected figure of 580 in September this year.

This 44% rise in the last three years is being accredited to the broad variety of A-level and vocational courses on offer, which are now attracting interest from youngsters from far beyond the designated high schools of Northgate and Neatherd in Dereham, and Litcham School.

To cope with the rising numbers, the school built a £130,000 cafe in October 2012 and, when the intake continued to rise, a further £180,000 was invested in a double eco-classroom to house psychology classes – one of the most popular of the 40 courses on offer.

Applications are regularly received from prospective students in Watton, Swaffham and King’s Lynn, while the pioneering Dereham Education and Soccer Academy, launched last year in partnership with Dereham Football Club, has attracted 29 young people.

But while celebrating its academic success and its wide appeal, college leaders are now exploring how to pay for the extra buildings needed to sustain this growth into the future.

Deputy director Chris Smith said the ideal solution would be a “new-build” block incorporating new classrooms and a new hall, which could cost as much as £500,000.

But with Norfolk’s education department confirming there is no extra funding available for post-16 places at the college, the question remains as to where this money could be found.

Mr Smith said: “The school roll has gone up by a significant amount. First of all, being successful is one of the key reasons for that, and we offer places to a huge variety of students because we are inclusive and we want them all to have an opportunity at post-16.

“One of the reasons why so many want to come here is that the students all say that we offer the benefits of a high school sixth form but it is a separate site so feels more like a sixth form college. This provides a really good stepping stone to university as they are encouraged to become more independent.

“One of the things happening in the background is that money going into schools is being cut, and the area it is being cut most is post-16. “Other sixth forms have really struggled but the way we look at it here is we don’t want to see students not getting an opportunity.

“We are at a stage where we have these numbers coming in and we have to make decisions on what to do with them. At the moment we don’t have a definite answer. The ideal scenario is a new-build with a couple of classrooms, and one of the things we are desperate for is a space where we can hold a large amount of people for exams and assemblies.”

Early ideas for a new development are to infill the existing “courtyard” area between the original Victorian building, the hall and the arts block – currently under-utilised as bike sheds and planters.

Mr Smith said: “If we suddenly had £500,000 we could do something very significant with it, but where do we get it? You can take out a loan with the local authority, but at the moment there is no central fund for schools’ development which we could go to in the past.

“The government will tell you we’ve been a victim of our own success. Ironically, what you have to do is prove you are over-run and hopefully then they can see a need for a greater building.”

A Norfolk County Council spokesman said: “It is good to see that the Dereham sixth form centre continues to recruit strongly and in recent years the county council has been able to support the centre with additional and improved accommodation.

“Post-16 providers now work within a national funding regime. Norfolk has been successful in securing funding for additional post-16 places but in this instance, the centre has not been eligible for such funding, as there are sufficient places in Norfolk overall for the type of courses available at the centre.”